1. Field of the Invention
The present invention relates to a method and apparatus for firing ceramic compacts used in electronic parts.
2. Description of the Related Art
In mass production of ceramic electronic parts and the like, green ceramic compacts are generally fired using a batch firing apparatus 1a such as set forth in FIG. 4. FIG. 4 is a cross-sectional view of the batch firing apparatus 1a, provided with a furnace 2a having a firing space 3a for green ceramic compacts therein. The furnace 2a comprises a furnace wall 4a including a ceiling and a side wall, a stage 10a as a hearth, a heater 5a provided along the furnace wall 4a in the furnace 2a, a gas inlet pipe 6a and a gas outlet pipe 7a provided in the ceiling of the furnace. Further, a lift 9a is provided under the stage 10a for raising and lowering the stage 10a. The furnace 2a is supported by legs 11a.
In the firing process of green ceramic compacts using the firing apparatus 1a, a casing 8a including many green ceramic compacts is put on the stage 10a and placed in the firing space 3a in the furnace 2a. The firing space 3a is heated with the heater 5a to fire the green ceramic compacts while supplying a given gas through the gas inlet and outlet pipes 6a and 7a. After the furnace 2a is cooled to a predetermined temperature, the stage is 10a lowered with the lift 9a to remove the fired ceramic compacts.
Since cooling in the furnace 2a of the ceramic compacts, which is fired at a high temperature, to room temperature requires a long time period, it is proposed in order to achieve faster cooling that the stage 10a be lowered with the lift 9a while the fired ceramic compacts having a high temperature are cooled by direct exposure to the open air.
However, such rapid cooling of fired ceramic compacts results in deterioration and fluctuation of electric characteristics of electronic parts comprising ceramic compacts due to the unstable cooling atmosphere.